Display retract mechanism

ABSTRACT

A display retract mechanism for moving a display between a retracted position and a deployed position is disclosed and explained. The display retract mechanism is useful, for example, in mounting a liquid crystal display within the cabin of a passenger vehicle, such as an aircraft or bus. A geared chain drive supplies torque necessary for rotating a pivot shaft on which the display is attached. The display is biased toward a retracted position by a gas spring with a substantially linear force curve between the retracted position and the deployed position. Also disclosed are an infrared sensor for detecting when the display is in the deployed position, a solenoid latch for holding the display in the retracted position, and an electromechanical clutch for maintaining the display in a particular position.

FIELD OF THE INVENTION

The invention pertains to mechanical devices for use in moving anoverhead display. Specifically, the invention is a mechanism fordeploying and retracting an overhead display.

BACKGROUND OF THE INVENTION

In a passenger vehicle it may be desirable for a display, such as avideo display, to be hidden when not in use. A mechanical device isnecessary for deploying and retracting the display. In mostenvironments, the mechanical device may also be subject to additionalconstraints such as size, weight, and power constraints. In someenvironments there may be additional constraints. For example, in anaircraft environment a mechanical device used for deploying andretracting an overhead display must automatically retract in the eventof power loss to the cabin, or in the event that the head of a passengerstrikes the display.

Traditional methods for deploying and retracting displays in passengervehicles include the use of linkage arms extending from a motor to amonitor to rotate the monitor to a pre-set viewing position. A slipclutch between the monitor and the motor allows for the display toretract when struck from a certain direction. A mechanical spring storesthe energy or automatic retract of the monitor in an emergency situationresulting in the loss of power.

Displays have been deployed and retracted by mechanisms linking themotor to the monitor by gears. The gear and motor linkage approach wearsat the pivot points and the monitor vibrates during transportationmaking viewing difficult. Vibrations in the display during transport maybe reduced with tighter tolerance gears, but tighter tolerance gearswould be ineffective from both weight and cost perspectives, and geartolerance will be lost with time and use.

Vibrations in the display have also been reduced by using a brake and bydriving a motor in reverse. The brake damps the vibrations transmittedto a display from a motor while the display is deploying, and maintainsthe display in a deployed position. The display is moved from thedeployed to a retracted position by first releasing the brake.Vibrations are damped while the display is retracting by driving themotor in reverse. The energy necessary to move the display from thedeployed to the retracted position is generally stored in a spring.Since driving the motor in reverse increases resistance to the movementof the display, a larger spring is required when this technique is usedfor damping vibrations. Often, larger springs create noisy whines whenthey are wound and unwound in this way.

In some passenger vehicles, the electromagnetic interference (“EMI”)generated by a display may also be an issue. Power and videodistribution systems use single stranded wires or combinations of flexand single stranded wires to distribute power. The power is distributedbetween the video board in the monitor assembly and the main chassis.The length of the wires, and the high frequencies of the video signalsbeing transmitted through them, together act like an antenna. Ingeneral, any mechanical device designed for deploying and retracting anoverhead display must attempt to mitigate the effects of EMI on thevideo signal transmitted to the display.

BRIEF SUMMARY OF THE INVENTION

The invention provides a display retract mechanism for moving a displayfrom a deployed position to a retracted position. The display retractmechanism includes a frame adapted for holding a display, a pivot shaft,a lever arm fixed to the pivot shaft, a gas spring, and a drivemechanism. The pivot shaft is attached to the frame along a pivot axis,and the pivot shaft rotates around the pivot axis from the retractedposition to the deployed position and back. The frame, which is adaptedfor holding the display, is attached to the pivot shaft along the pivotaxis so that as the pivot shaft rotates around the pivot axis the frame,which holds the display, moves from the retracted position to thedeployed position. The gas spring is hingedly connected to the leverarm, which is in turn fixed to the pivot shaft. The arrangement allowsfor the display to be retracted when power to the drive mechanism isoff.

The present invention also provides a facility for detecting when themonitor is in a retracted position. In an embodiment, there is providedan infrared transmitter for supplying an infrared signal. As will berecognized by those of skill in the art, other types of transducers,including ultrasonic, electro-optic, or electromechanical are alsopossible. The detector of the present invention could be any one of avariety of such transducers. The infrared signal is received by aninfrared sensor, which produces a status signal when the infrared signalis received. When the display is in the retracted position, a pinmounted on the frame blocks the infrared signal, preventing the infraredsignal from reaching the infrared sensor. The status signal produced bythe infrared signal is supplied to a printed circuit board, where it isuseful for producing a control signal. The printed circuit board isoptionally connected with power and video connectors. The EMI with videosignals sent between the printed circuit board and the display isadvantageously reduced through the use of a cross-hatched slip pastcable.

In an embodiment of the present invention, the drive mechanism includesa motor for driving a motor shaft; a drive shaft; a mechanical couplerfor joining the motor shaft to the drive shaft; a first gear on thedrive shaft; a second gear on a gear shaft, the first gear in mechanicalcontact with the second gear; a first sprocket attached to the gearshaft; a second sprocket attached to the pivot shaft; a chain mounted onboth the first sprocket and the second sprocket, whereby the torque fromthe gear shaft is transmitted to the pivot shaft; a motor controllercard for producing a motor drive signal in response to the controlsignal from the printed circuit board; and a power supply for supplyinga power to the display retract mechanism. Optionally, anelectromechanical clutch mechanism may be provided to the drivemechanism for selectively engaging and disengaging the drive mechanism.In addition, a solenoid latch optionally may be provided to the displayretract mechanism for locking the frame into the retracted position. Thegear ratio of the first gear to the second gear is about 200 to 1. Therelatively low gear ratio is an advantage of the present invention.

The display retract mechanism may optionally provide a housing, to whichthe pivot shaft may be mounted. The housing is adaptable for receivingthe frame when the display is in the retracted position. The housing isnot necessary to the present invention; rather, it is a convenienceallowing for simpler installation and de-installation of the device,providing a single mechanical structure to which some parts of thedevice may be attached. It will be understood by those of skill in theart that the housing is not necessary to the function of the presentinvention.

In a preferred embodiment of the present invention, the frame and thehousing are fabricated from a material that is mechanically strong, heatresistant, and burns with low toxicity. The frame and the housing may befabricated from a material selected from the group consisting ofpolyetherimide or polyphenylsulfone. In addition, the housing may becoated with a copper epoxy resin, which includes a mixture of coppermicro-spheres. EMI produced by the display retract mechanism isadvantageously reduced through the use of the copper epoxy resin.

In addition, the present invention provides a method for moving adisplay from a deployed position to a retracted position. The methodincludes the following steps: holding the display in a frame; rotating apivot shaft around a pivot axis, the frame attached to the pivot shaftalong the pivot axis; fixing a lever arm to the pivot shaft, the leverarm compressing a gas spring as the pivot shaft is rotated around thepivot axis from the retracted position to the deployed position; andsupplying torque to the pivot shaft for rotating the pivot shaft fromthe retracted to the deployed position with the drive mechanism. Themethod may optionally include the further steps of generating aninfrared signal; receiving the infrared signal in order to produce astatus signal; blocking the infrared signal with a pin in order toprevent the receiving of the infrared signal; and processing the statussignal in order to produce a controlled signal. In an optional finalstep, the pivot shaft may be attached to a housing, the housing adaptedfor receiving the frame when the display is the retracted position.

The power and video distribution system of the present invention maycombine all power and video cables to the LCD in a cross-hatched,slip-past, flexible cable. The cable is chosen for its ability towithstand multiple flex cycles, and for its ability to shield from EMI.

The display retract mechanism also uses a gas spring to retract themonitor. The gas spring provides a near linear force curve for the rangeof actuation, requiring less power from the drive mechanism, andallowing for smoother operation of the display retract mechanism as awhole. The combination of the clutch, motor, and gas spring of thepresent invention provides a quieter display retract mechanism than hasbeen conventionally available.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, advantages, and features of the presentinvention will be apparent from the following detailed description andthe accompanying drawings, in which:

FIG. 1 is a perspective view of a housing for a display retractmechanism in accordance with an embodiment of the present invention;

FIG. 2 is a perspective view of the drive mechanism in accordance withan embodiment of the present invention;

FIG. 3 is an exploded view of a display retract mechanism in accordancewith an embodiment of the present invention;

FIG. 4 a is a side view of a display retract mechanism with the displayin a retracted position in accordance with an embodiment of the presentinvention;

FIG. 4 b is a side view of a display retract mechanism with the displayin a partially deployed position in accordance with an embodiment of thepresent invention;

FIG. 4 c is a side view of a display retract mechanism with the displayin a deployed position in accordance with an embodiment of the presentinvention;

FIG. 5 is a perspective view of a display in a deployed position inaccordance with an embodiment of the present invention;

FIG. 6 is an exploded view of a frame for a display for use with adisplay retract mechanism in accordance with an embodiment of thepresent invention;

FIG. 7 is a detail of the frame assembly shown in FIG. 6 in accordancewith an embodiment of the present invention; and

FIG. 8 is a state diagram showing the logical states of a displayretract mechanism in accordance with an embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

In a passenger vehicle, such as an aircraft, it is desirable foroverhead displays to be mounted in close proximity to a passenger. Theunderside of an overhead bag bin is preferable to the ceiling of anaisle because many displays are best viewed at close proximity, from aviewing angle perpendicular to the plane of the display. However, adisplay mounted on the underside of an overhead bag bin may create anobstruction to passengers, for example, by hindering a passenger fromentrance to or exit from a seat. Hence, it is desirable for a device tobe provided that serves to stow a display in a retracted position whennot in use. The present invention provides a display retractionmechanism for rotating an overhead display, such as might be mountedunderneath a bag bin on an aircraft, between a retracted and a deployedposition.

The advantages of the present invention are obtained in part through theuse of a chain drive with a low gearing ratio, a gas spring for biasingthe display towards the retracted position, an infrared transmit andreceive sensor, an electromagnetic clutch, and a housing and cablesdesigned to minimize EMI.

Although it is not necessary to the method or system of the presentinvention, it is desirable for a housing 10 to be provided to thepresent invention. An embodiment of a housing for a display retractmechanism is shown in FIG. 1. The housing 10 is comprised of a base 20and a back cover plate 30. The back cover plate 30 is secured to thebase 20 by fasteners 32. The base 20 comprises a base front 22, a baseplate 23, and a base back 26 (the base bay 24 is hidden beneath the backcover plate 30 in FIG. 1). A gas spring 40 on a gas spring mount 42 isshown. Standard video signal connectors (as are recognized by those ofskill in the art), including a power connector 160 and a video connector162 are also shown in FIG. 1.

The primary source of energy for rotating the display from a retractedposition to a deployed position is provided by the drive mechanismshown, in an embodiment, in FIG. 2. The gas spring 40 comprises a gasspring barrel 41 and a gas spring rod 44. The end of the gas spring rod44 is hingedly connected to a lever arm 90 by its forked end 46. Thelever arm 90, which serves to transmit force from the gas spring 40 tothe pivot shaft 84, is fixed to the pivot shaft 84 by a suitable fixingmeans, such as a screw, bolt, or epoxy. Other fixing means, such as aweld, are suitable also. As will be understood by those of ordinaryskill in the art, the lever arm 90 need not have the specific shapeshown in FIG. 2. Other mechanical means, for example, a lever arm ofdifferent shape, a linkage arm, or a hook, may be used as a lever arm 90for connecting the gas spring to the pivot shaft, thereby transmittingthe bias force from the gas spring to the pivot shaft. The pivot shield200 and the base 20 are cut-away in FIG. 2 so that the interior of thehousing 10 is visible, including the printed circuit board 170, thecables 172 and 174, and the power connector 160 and video connector 162.

The energy required to oppose the force of the gas spring is generatedby the motor 50 which receives power and control signals from theprinted circuit board 170 through a cable 172. The motor shaft (hiddenbehind the mechanical coupler 52 in FIG. 2) for the motor 50 isconnected to drive shaft 62 through the mechanical coupler 52. Anelectromechanical clutch 60 is provided with power and control signalsfrom the printed circuit board 170 through a cable 174. The drive shaft62 is connected to a first gear 64, and the teeth of the first gear meshwith the teeth of a second gear 70 on a gear shaft 72. Also mounted onthe gear shaft 72 is a first sprocket 82. The first sprocket 82 hasteeth provided for holding a chain 80. The chain 80 transmits rotationalmomentum from the gear shaft 72 to the pivot shaft 84, on which a secondsprocket 83 is mounted, also having teeth provided for holding the chain80.

Also shown in FIG. 2 is the slip past cable 180 by which the printedcircuit board 182 is connected to the display (not shown in FIG. 2).Power and data are supplied to the printed circuit board 170 through apower connector 160 and a video connector 162.

The various components of the display retract mechanism, according to anembodiment of the present invention, are shown disassembled in FIG. 3.The base 20, which is part of the housing 10, comprises four parts,including a base front 22, a base plate 23, a base bay 24, and a baseback 26. All or some of these parts may be coated with a copper epoxyresin, which includes a mixture of copper micro-spheres. The copperepoxy resin provides additional EMI shielding by providing a stronglyconducting layer between the electronics within the housing 10 and therest of the passenger vehicle in which the present invention is mounted.

The base front 22 provides shielding from EMI, as well as a mechanicalbarrier between the drive mechanism and another device that might existin a passenger vehicle in which the present invention is mounted. Thebase front 22 is fixed to the base plate 23 with a suitable mechanicaldevice for attachment, such as a screw, bolt, or epoxy.

The base bay 24 is part of the same physical material as the base plate23, and constitutes a recess shielded from EMI in which the printedcircuit board 182 may be mounted and to which the back cover plate 30may be partially fixed. In the embodiment of the invention shown in FIG.3, the gas spring mount 42 is attached beside the base bay 24, fixeddirectly to the base plate 23 with a suitable mechanical device forattachment, such as a screw, bolt, or epoxy. The base back 26 provides amount for the power connector 160 and video connector 162, and is alsofixed to the base plate 23 with a screw, bolt, or epoxy. The base back26 also provides part of the support for the back cover plate 30.

The pivot shield 200 is also fixed to the base plate 23 with a suitablemechanism for fixing, such as a screw, bolt, or epoxy, and serves toprovide shielding from EMI and prevents interference from anothermechanical device with the drive mechanism. The drive mechanism,including the motor 50, mechanical coupler 52, electromechanical clutch60, second gear 70, gear shaft 72, and chain 80 are also shown in FIG.3. Finally, the front cover 250 is shown in the retracted position inFIG. 3.

The series of FIGS. 4 a–c show an embodiment of how the presentinvention moves a display from the retracted position (FIG. 4 a) to thedeployed position (FIG. 4 c), with a partially deployed/retractedposition in between (FIG. 4 b).

On the drive shaft 62 is mounted a first gear 64, with teethinterleaving the teeth of a second gear 70. The first gear 64, is fixedto the drive shaft 62, so that, when the motor 50 (not shown in FIG. 4a) rotates the motor shaft (not shown in FIG. 4 a), the angular momentumof the motor shaft is transmitted through the mechanical coupler 52 (notshown in FIG. 4 a) to the drive shaft 62, turning the first gear 64 in acounter-clockwise direction. As the first gear 64 rotatescounter-clockwise, the second gear 70 is driven clockwise (in thedirection of the arrow shown). The second gear 70 is fixed to the gearshaft 72 so that when the second gear 70 turns, it transmits its angularmomentum through the gear shaft 72 to the first sprocket 82, which isalso fixed to the gear shaft 72. Around the teeth of the first sprocket82 is mounted a chain 80. The chain 80 serves to transmit the angularmomentum of the clockwise rotating first sprocket 82 to the secondsprocket 83, which is mounted on the pivot shaft 84. Hence, the drivemechanism supplies a torque to the pivot shaft that opposes the forcegenerated by the gas spring 40, which is biased toward the retractedposition. The choice of motor 50, first gear 64, and second gear 70 mustbe made considering the strength of the force generated by the gasspring 40, which will vary with embodiments of the present invention.Such a choice could be made readily by one of ordinary skill in the art.In the presently preferred embodiment of the invention, the gearingratio is about 200:1 (substantially less than the 1000:1 ratios familiarin previous retract mechanisms).

Also shown in FIG. 4 a is a solenoid latch 134, with a spike 130extending toward the frame 100. A recess (not shown) in the frame 100 isprovided, into which the spike 130 extends. The spike 130, when extendedinto the recess, is capable of maintaining the display in the retractedposition.

As the pivot shaft 84 is rotated by the drive mechanism in the clockwisedirection, the lever arm 90, which is attached to the pivot shaft eitherdirectly or indirectly, through the second sprocket 83, is rotated. Whenthe lever arm 90 rotates, the gas spring rod 44 (hingedly connected tothe lever arm 90 by its forked end 46) is pushed into the gas springbarrel 42. Hence, the frame 100, which is fixed to the other end of thelever arm 90, moves into a partially deployed position, as shown in FIG.4 b. Note that the main differences between FIG. 4 a and FIG. 4 b arethe shown length of the gas spring rod 44 (shorter in FIG. 4 b becausethe gas spring rod 44 has been pushed into the gas spring barrel 42) andthe position of the frame 100. As the same motion continues, the displayis moved finally into a fully deployed position, shown in FIG. 4 c. Notealso that in FIGS. 4 b and 4 c the latch 134 has withdrawn the spike(130 in FIG. 4 a), which is necessary for the display to be deployed.

A plastic pin 410 disposed on the front cover 250 of the frame 100(shown in FIGS. 4 a–c) on an edge of the frame 100 near the pivot axis708. (The pivot axis 708 is not expressly shown in FIGS. 4 a–c, but isshown as a line passing through the center of the pivot shaft 84, whichis perpendicular to the plane of the second sprocket 83 in FIG. 7.). Theplastic pin 410 blocks an infrared signal, produced by an infraredtransmitter, from hitting an infrared photo sensor 400 when the displayfirst reaches the deployed position. The infrared photo sensor 400, notreceiving the infrared signal anymore, begins sending a status controlsignal to the printed circuit board 182 that indicates to the printedcircuit board that the display 120 is now in the deployed position. If,during movement, the display 120 meets a threshold level of force, themotor 50 or the clutch 60 will disengage, and the display 120 willreturn (using the energy stored in the gas spring 40) to the retractedposition. During normal operation, the clutch 60 is engaged while themotor 50 is moving the display 120 from the retracted position to thedeployed position. The clutch 60 is also engaged while the display 120is held in the deployed position.

A perspective view of the display 120 as it might appear deployed in apassenger vehicle is shown in FIG. 5. The front cover 250 keeps thedisplay 120 with the frame 100. The under side of the housing 10 is alsoshown in FIG. 5.

In some environments, for example, in aircraft environments, there areconstraints on the manner in which a display retract mechanism mayoperate. In the United States of America, the Federal AviationAdministration (FAA) requires that all under-bag-bin displays retractautomatically in the event of power loss to the cabin during flight. Aswould be obvious to one of ordinary skill in the art, this requirementis naturally met by the device as disclosed and explained in connectionwith FIGS. 1–5. When power is no longer supplied to the presentinvention, the clutch 60 de-energizes and decouples the motor 50 fromthe gas spring 40, the gas spring 40 then smoothly retracts the displayinto a retracted position.

The FAA has set an additional requirement, colloquially referred to asthe “headstrike” requirement, which demands that a display retract whena force surpassing a given threshold force is applied to a display, forexample, when the head of a passenger strikes the display upon entranceto or exit from a seat. The facility of the present invention forhandling this requirement is provided by the electromechanical clutch 60(shown in FIG. 2). In combination with the printed circuit board 182 (towhich the electromechanical clutch 60 is connected by a bundled powerand data cable 174), the present invention is capable of sensing whenthe threshold force (as specified by the FAA) has been applied to thedisplay, and the display is moved from the deployed position to theretracted position when that force has been applied. Further details onthis state of operation are provided in FIG. 8, and in the descriptiontherefor below. The same facility is also effected for retracting thedisplay in the event that it should encounter an obstruction whiledeploying.

FIG. 6 illustrates the assembly surrounding the display 120 and theframe 100. The display 120 and the frame 100 are situated between a backcover 270 and a front cover 250, with a protective screen 260 fixedbetween the display 120 and the front cover 250.

A more detailed view of one corner of the frame 100 is shown in FIG. 7.The frame 100 provides a mechanical support for the cross-hatched cable180 to interface with the display 120 (not shown in FIG. 7). Inaddition, the lever arm 90 is fixed with screws 702 to the frame 100. Ahinge 704, with several washers 706, hingedly connects the forked end 46of the gas spring 40 (not shown in FIG. 7) to the lever arm 90. Inaddition, the frame 100 is physically connected along the pivot axis(shown as the dotted line 708) to the pivot shaft 84. The secondsprocket 83, a bolt 710, and a washer 706 are also shown in FIG. 7

A control circuit, including, for example, a microprocessor with memory,is used to keep track of the logical state of the display retractmechanism, and to control its operation. In the present invention, thecontrol circuit is provided as part of the printed circuit board 182.The logical state of the display retract mechanism is defined by keepingtrack of the current and previous states of the various components ofthe system, including the motor 50, the electromechanical clutch 60, thesolenoid latch 134, the infrared photo sensor 400, and a clock andincrement counter in the control circuit of the printed circuit board182. Using the feedback and control provided by the foregoing, one ofordinary skill in the art may program the control circuitry of theprinted circuit board 182 to maintain the display retract mechanism inthe following well-defined logical states.

The retracted state 800 corresponds to a logical state in which thedisplay is in the retracted position, with the electromechanical clutch60 disengaged, and the solenoid latch 134 closed (with the spike 130providing mechanical support for the weight of the frame 100, as shownin FIG. 41). The power to the motor 50 and clutch 60 may be off,although power may still be provided to the control circuit on theprinted circuit board 182.

On receiving a deploy signal, which may be self-generated by the controlcircuit on the printed circuit board 182, or, alternatively, may bereceived from an external source in communication with the printedcircuit board 170 through the power connector 160 or the video connector162, the control circuit starts operating the display retract mechanismin the deploying state 810. In the deploying state 810, a clock on theprinted circuit board 182 begins counting up, and an increment counteron the printed circuit board 182 is initializes to one. The solenoidlatch 134 is released, retracting the spike 130, the electromechanicalclutch 60 is engaged, and the motor 50 is powered. In the deployingstate 810, the display retract mechanism might appear as shown in FIG. 4b.

One of several error states may occur in sequence after the deployingstate 810. Using the clock on the printed circuit board 182, the controlcircuit keeps track of how long the display has been in the deployingstate 810. While deploying, the infrared photo sensor 400 will remainopen (as shown by the box labeled 815). If the infrared photo sensor 400does not close before a preset length of time, then the deploy is timedout 845. An obstruction is preventing the device from deploying in anormal length of time. The clutch 60 allows the motor 50 to rotate evenwhen the display 120 is prevented from deploying because of anobstruction.

When the deploy is timed out 845, the display retract mechanism willautomatically begin retracting. The retracting state due to obstruction840 occurs only when the normal deploying state 810 does not result in anormal deployed state 820, for example, for a reason already discussed,i.e., when the deploy is timed out 845.

When the deploying state 810 moves into the retracting due toobstruction state 840, the increment counter is incremented by one. Forexample, if the display was in the deploying state 810 for the firsttime since it was in the retracted state 800, then the increment counterwill be incremented from one to two when it is put into the retractingdue to obstruction state 840. In addition, the clock is reset.

Three different cases are possible for what logical state will followthe retracting due to obstruction state. In two cases, the displayretract mechanism may proceed from the retracting due to obstructionstate 840 back to the deploying state 810. In the first case, if theincrement counter is less than three, and the deploy had timed out 845on its last deploy attempt, then the display retract mechanism re-entersthe deploying state 810. In the second case, if the override switch 855,which is provided on the exterior of the device, is activated, then thedevice re-enters the deploying state 810. The override switch 855 allowsa human to retake control should the device end up in an ill-definedstate. In the third case, the display retract mechanism proceedsdirectly to the retracted state 800. The third case results when thedeploying state 810 has timed out for a second time, so that theincrement counter now registers three, which results in a retract timeout 860. Having returned to the retracted state 800 from the retractingdue to obstruction state 840, the display retract mechanism will notbegin deploying again until it receives another deploy signal.

Returning to a description of the normal states of operation, there isshown in FIG. 8 how the display retract mechanism may progress from adeploying state 810 to a deployed (photo sensor=closed) state 220.During the deploying, the photo sensor will remain open 815, allowing acontrol signal to be sent back to the printed circuit board 182, thatindicates that the display retract mechanism must remain in thedeploying state 810. After the display 100 has reached the deployedposition, a plastic pin 410 (mounted on the front cover 250 in anembodiment of the present invention) blocks an infrared signal from aninfrared transmitter from being received by the infrared photo sensor400, i.e., the photo sensor is closed. Hence, the control signal sent tothe printed circuit board 182 now indicates that the display 100 is inthe deployed position. The deployed state 820 is characterized by astate in which the motor 50 is stopped, but the clutch 60 remainsengaged, holding the display 100 in the deployed position except in theevent of power loss, at which time the display 100 will smoothly retract(using the energy stored in the gas spring 40) into the retractedposition.

In an embodiment, the printed circuit board 182 receives a retractsignal in the same way that it receives a deploy signal. Upon receipt ofa retract signal, the clutch 60 is disengaged, and the display 100smoothly retracts in the retracted position (in substantially the sameway that it would were the power to the display retract mechanism turnedoff. Having returned to the retracted position 800, the device is readyto begin the cycle again with another deploy signal.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) are to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. Recitation of ranges of values herein are merely intended toserve as a shorthand method of referring individually to each separatevalue falling within the range, unless otherwise indicated herein, andeach separate value is incorporated into the specification as if it wereindividually recited herein. All methods described herein can beperformed in any suitable order unless otherwise indicated herein orotherwise clearly contradicted by context. The use of any and allexamples, or exemplary language (e.g., “such as”) provided herein, isintended merely to better illuminate the invention and does not pose alimitation on the scope of the invention unless otherwise claimed. Nolanguage in the specification should be construed as indicating anynon-claimed element as essential to the practice of the invention.

Preferred embodiments of this invention are described herein, includingthe best mode known to the inventors for carrying out the invention. Ofcourse, variations of those preferred embodiments will become apparentto those of ordinary skill in the art upon reading the foregoingdescription. The inventors expect skilled artisans to employ suchvariations as appropriate, and the inventors intend for the invention tobe practiced otherwise than as specifically described herein.Accordingly, this invention includes all modifications and equivalentsof the subject matter recited in the claims appended hereto as permittedby applicable law. Moreover, any combination of the above-describedelements in all possible variations thereof is encompassed by theinvention unless otherwise indicated herein or otherwise clearlycontradicted by context.

1. A display retract mechanism for moving a display from a deployedposition to a retracted position, comprising: a frame adapted forholding a display; a pivot shaft defining a pivot axis, the pivot shaftrotatable around the pivot axis from the retracted position to thedeployed position; a lever arm fixed to the pivot shaft; a gas springbiased toward the retracted position, the gas spring hingedly connectedto the lever arm; a drive mechanism for rotating the pivot shaft aroundthe pivot axis from the retracted to the deployed position, and whereinthe gas spring substantially freely moves the pivot shaft from thedeployed position toward the retracted position when the drive mechanismreleases the pivot shaft.
 2. The display retract mechanism of claim 1,further comprising: a detector for determining when the frame is in theretracted position.
 3. The display retract mechanism of claim 2, whereina cross-hatched slip past cable connects the display to a printedcircuit board.
 4. The display retract mechanism of claim 3, wherein theprinted circuit board is connected to a power connector.
 5. The displayretract mechanism of claim 3, wherein the printed circuit board isconnected to a video connector.
 6. The display retract mechanism ofclaim 2, the drive mechanism comprising: a motor for driving a motorshaft; a drive shaft; a mechanical coupler for joining the motor shaftto the drive shaft; a first gear on the drive shaft; a second gear on agear shaft, the first gear in mechanical contact with the second gear; afirst sprocket attached to the gear shaft; a second sprocket attached tothe pivot shaft; a chain mounted on both the first sprocket and thesecond sprocket, whereby the torque from the gear shaft is transmittedto the pivot shaft; a motor controller card for producing a motor drivesignal in response to the control signal from the printed circuit board;and a power supply for supplying power to the display retract mechanism.7. The display retract mechanism of claim 6, further comprising: aclutch mechanism for selectively engaging and disengaging the drivemechanism.
 8. The display retract mechanism of claim 6, furthercomprising: a latch for locking the frame into the retracted position.9. The display retract mechanism of claim 6, wherein the gear ratio ofthe first gear to the second gear is about 200:1.
 10. The displayretract mechanism of claim 1, further comprising: a housing to which thepivot shaft is mounted, the housing adaptable for receiving the frame inthe retracted position.
 11. The display retract mechanism of claim 10,wherein the frame and the housing are fabricated from a materialselected from the group consisting of polyetherimide orpolyphenylsulfone.
 12. The display retract mechanism of claim 10,wherein the housing is coated with a copper epoxy resin.
 13. The displayretract mechanism of claim 10, wherein the motor controller card, thepower supply, and the printed circuit board are mounted to the housing.14. A display retract mechanism for moving a display from a deployedposition to a retracted position, comprising: a frame adapted forholding a display; a pivot shaft defining a pivot axis, the pivot shaftrotatable around the pivot axis from the retracted position to thedeployed position; a lever arm fixed to the pivot shaft; a gas springbiased toward the retracted position, the gas spring hingedly connectedto the lever arm; a drive mechanism for rotating the pivot shaft aroundthe pivot axis from the retracted to the deployed position; a housing towhich the pivot shaft is mounted, the housing adaptable for receivingthe frame in the retracted position, and wherein the gas springsubstantially freely moves the pivot shaft from the deployed positiontoward the retracted position when the drive mechanism releases thepivot shaft.
 15. The display retract mechanism of claim 14, furthercomprising: a detector for determining when the frame is in theretracted position.
 16. The display retract mechanism of claim 14,further comprising: a cross-hatched slip past cable that connects thedisplay with a printed circuit board.
 17. The display retract mechanismof claim 16, wherein the printed circuit board is connected to a powerconnector.
 18. The display retract mechanism of claim 16, wherein theprinted circuit board is connected to a video connector.
 19. The displayretract mechanism of claim 14, wherein the frame and the housing arefabricated from a material selected from the group consisting ofpolyetherimide or polyphenylsulfone.
 20. The display retract mechanismof claim 14, wherein the housing is coated with a copper epoxy resin.21. The display retract mechanism of claim 14, further comprising: alatch for locking the frame into the retracted position.
 22. The displayretract mechanism of claim 14, the drive mechanism comprising: a motorfor driving a motor shaft; a drive shaft; a mechanical coupler forjoining the motor shaft to the drive shaft; a first gear on the driveshaft; a second gear on a gear shaft, the first gear in mechanicalcontact with the second gear; a first sprocket attached to the gearshaft; a second sprocket attached to the pivot shaft; a chain mounted onboth the first sprocket and the second sprocket, whereby the torque fromthe gear shaft is transmitted to the pivot shaft; a motor controllercard for producing a motor drive signal in response to the controlsignal from a printed circuit board; and a power supply for supplyingpower to the display retract mechanism.
 23. The display retractmechanism of claim 22, further comprising: a clutch mechanism forselectively engaging and disengaging the drive mechanism.
 24. Thedisplay retract mechanism of claim 22, wherein the gear ratio of thefirst gear to the second gear is about 200:1.
 25. The display retractmechanism of claim 22, wherein the motor controller card, the powersupply, and the printed circuit board are mounted to the housing.
 26. Adisplay retract mechanism for moving a display from a deployed positionto a retracted position, comprising: a frame for holding a display; apivot shaft, the frame attached thereto along a pivot axis, the pivotshaft rotatable around the pivot axis from the retracted position to adeployed position; a lever arm attached to the pivot shaft; a gas springbiased toward the retracted position, the gas spring hingedly connectedto the lever arm; detector means for detecting when the display is inthe retracted position; drive means for supplying torque to the pivotshaft, in order to rotate the frame around the pivot axis from theretracted position to the deployed position, and wherein the gas springfreely moves the pivot shaft from the deployed position toward theretracted position when the drive means releases the pivot shaft. 27.The display retract mechanism of claim 26, wherein a cross-hatched slippast cable connects the display to a printed circuit board.
 28. Thedisplay retract mechanism of claim 27, wherein the printed circuit boardis connected to a power connector.
 29. The display retract mechanism ofclaim 27, wherein the printed circuit board is connected to a videoconnector.
 30. The display retract mechanism of claim 26, furthercomprising: a clutch mechanism for selectively engaging and disengagingthe drive mechanism.
 31. The display retract mechanism of claim 26,further comprising: a latch for locking the frame into the retractedposition.
 32. The display retract mechanism of claim 26, wherein thegear ratio of the first gear to the second gear is about 200:1.
 33. Thedisplay retract mechanism of claim 26, further comprising: a housing towhich the pivot shaft is mounted, the housing adaptable for receivingthe frame in the retracted position.
 34. The display retract mechanismof claim 33, wherein the frame and the housing are fabricated from amaterial selected from the group consisting of polyetherimide orpolyphenylsulfone.
 35. The display retract mechanism of claim 33,wherein the housing is coated with a copper epoxy resin.
 36. The displayretract mechanism of claim 33, wherein the motor controller card, thepower supply, and a printed circuit board are mounted to the housing.37. A method for moving a display from a deployed position to aretracted position, the method comprising the steps of: holding thedisplay in a frame; rotating a pivot shaft around a pivot axis, theframe attached to the pivot shaft along the pivot axis; fixing a leverarm to the pivot shaft, the lever arm compressing a gas spring as thepivot shaft is rotated around the pivot axis from the retracted positionto the deployed position; supplying torque to the pivot shaft forrotating the pivot shaft from the retracted to the deployed positionwith a drive mechanism, and allowing the gas spring to substantiallyfreely move the pivot shaft from the deployed position to the retractedposition when the drive mechanism releases the pivot shaft.
 38. Themethod of claim 37, further comprising the steps of: generating adetector signal; receiving the detector signal in order to produce astatus signal; blocking the detector signal with a pin in order toprevent the receiving of the detector signal; and processing the statussignal in order to produce a control signal.
 39. The method of claim 38,further comprising the step of: attaching the pivot shaft to a housing,the housing adapted for receiving the frame when the display is in theretracted position.
 40. The method of claim 37, further comprising thestep of: using an electromechanical clutch to hold the display in place.41. The display retract mechanism of claim 1, further comprising: aclutch for selectively engaging and disengaging the drive mechanism. 42.The display retract mechanism of claim 41, further comprising: adetector for determining when the frame is in the retracted position.43. The display retract mechanism of claim 41, wherein a cross-hatchedslip past cable connects the display to a printed circuit board.
 44. Thedisplay retract mechanism of claim 43, wherein the printed circuit boardis connected to a power connector.
 45. The display retract mechanism ofclaim 43, wherein the printed circuit board is connected to a videoconnector.
 46. The display retract mechanism of claim 41, wherein theclutch includes an electromechanical clutch.
 47. The display retractmechanism of claim 41, the drive mechanism comprising: a motor fordriving a motor shaft; a drive shaft; a mechanical coupler for joiningthe motor shaft to the drive shaft; a first gear on the drive shaft; asecond gear on a gear shaft, the first gear in mechanical contact withthe second gear; a first sprocket attached to the gear shaft; a secondsprocket attached to the pivot shaft; a chain mounted on both the firstsprocket and the second sprocket, whereby the torque from the gear shaftis transmitted to the pivot shaft; a motor controller card for producinga motor drive signal in response to the control signal from the printedcircuit board; and a power supply for supplying power to the displayretract mechanism.
 48. The display retract mechanism of claim 47,further comprising: a latch for locking the frame into the retractedposition.
 49. The display retract mechanism of claim 47, wherein thegear ratio of the first gear to the second gear is about 200:1.
 50. Adisplay retract mechanism as claimed in claim 46, wherein: the gasspring substantially freely moves the pivot shaft from the deployedposition to the retracted position when the clutch disengages the drivemechanism.